This is not a "plz show me teh codes" kind of board. If you want someone to do work for you, pay them using the hire-a-programmer board.

If you want to do this yourself, start doing it. Northie already told you the basics: Submit the form but don't save it. Print it as though it's been submitted, then re-print the form with all the user's inputs directly below the re-printing and allow them to edit or confirm.

can i just add that this method of regurgitating user data back to them to "confirm" is very old school. Users are not stupid that they will enter bad data.. if their intention is bad that is another thing in which case your validation/security script would stop them. For a normal user it is a "little" bit inconvenient

Yeah, the most common method these days is simply allowing users to delete or edit their existing information. Facebook doesn't allow preview OR edit. Just post. Reddit allows edit and delete, but no preview. Various CMSes do in-line previews where your content is printed directly above the input box so you can see if your formatting is effective. Only older message boards like devshed have a "preview" button.